1. Field of the Invention
The present invention relates to the field of eyeglass retainers, and is more particularly directed to an improved retainer which connects the temple pieces of an eyeglass frame around the rear of the head of the eyeglass wearer.
2. State of the Prior Art
A variety of eyeglass retainers are known and in use. Two distinct types are known. One is a retainer designed to allow the wearer to remove his eyeglasses and leave them dangling from his neck. Such retainers are not designed to better secure the eyeglasses in position during use. The second known type of retainers accomplish this latter function and are suited for use during sporting or other activities so as to prevent accidental loss of the eyeglasses.
Of the first type, various retainers are known which consists of a string, band or strap which is provided with attachment means at each end, for example, clips or other fasteners for securing the ends of the retainer to the temple pieces of a pair of eyeglasses. The length of the retainer strap in such cases is sufficiently long to allow the eyeglasses to hang loosely from the person's neck when they are not in position for use. During use, the retainer hangs loosely behind the wearer's head. Exemplary of such retainers are the devices disclosed in U.S. Pat. Nos. 2,481,946 to Pendleton, 2,539,922 to Nyberg, and 2,704,961 to Weil.
Of the other type of eyeglass retainer, one device is disclosed by Fuller in U.S. Pat. No. 4,133,604, which comprises an elastic band provided with tubular ends which slide onto and grip the temple pieces of a pair of eyeglasses. While this device performs adequately, it is constructed by sewing together the edges of an originally flat band of elastic material. Still other eyeglass retainers are disclosed in U.S. Pat. Nos. 3,450,467 to Phillips, 3,502,396 to Greenberg, and 1,819,738 to Daniels.
Seron in U.S. Pat. No. 3,874,776 and Lawrence in U.S. Pat. No. 3,879,804 disclose fasteners for attaching a strap or retainer cord to the frame of a pair of eyeglasses.
Attempts have been made in the past to make eyeglass retainers from tubing made of textile fabric, particularly small diameter tubes made of knitted elastic fiber, known as draw cord in the knitting industry. In general, such a retainer is constructed by cutting a length of said cord or tubing to an appropriate length, and inserting one of the temple pieces of the eyeglass frame into each of the open ends of the tube. The diameter of the tube is selected so as to snuggly slide over and retain the temple pieces of the eyeglass within the tube. Two problems have been encountered in the past with such devices. Firstly, unless the ends of the textile tube are terminated or finished in some way, the fabric will increasingly fray with use, such that the ends of the tube will lose their tubular structure and elasticity and eventually become inadequate for securely retaining the temple pieces of the eyeglass frame. A further problem encountered in the past has been the need to provide adequate gripping force of the tube about the eyeglass temple piece or bow while maintaining ease of attachment of the retainer to the tube. This latter difficulty has been aggravated in some cases because of the insufficient elasticity of the knitted fabric used, which is thus unable to securely grip the eyeglass temple piece.
Solutions have been restored to in the past to overcome these two problems have included dipping the ends of the textile tube in a liquid, such as an adhesive, which hardens upon drying so as to increase the stiffness of the ends of the retainer tube against stretching or bending, thereby improving its gripping or retaining capabilities about the temple piece. The adhesive also tends to keep the unfinished ends of the knitted tube against excessive fraying, but does not stop completely the fraying process. Such eyeglass retainers tend to be unsightly, and do not perform adequately or reliably since after a period of use the rubber adhesive typically used for dipping the tube ends cracks and is no longer able to reinforce the tube as intended.
Another expedient adopted in the past has been the use of short lengths of rubber tubing, such as surgical tubing, inserted into or otherwise attached to each end of the knitted tube, as exemplified by the above refernced patents to Weil and Pendleton. Although this is a more reliable solution to the problem, it substantially raises the cost of manufacture of the device since additional materials are required, and also additional labor is necessary to insert and secure the surgical tubing within the knitted tube.
Thus, a continuing need exists for improvements in eyeglass retainers made of knitted fabric.